STM32F401RE 的 PWM 问题

Question

我正在使用 Nucleo 板来实现我的恶作剧，我的芯片上有这个 PA5 引脚，它连接到板上的 LED2，可以生成 PWM 信号，但它没有，我也不清楚解决它

  RCC->APB1ENR |= RCC_APB1ENR_TIM2EN;
  RCC->AHB1ENR |= RCC_AHB1ENR_GPIOAEN;
  GPIOA->MODER |= ( 0x2UL << GPIO_MODER_MODE5_Pos); //alternate mode
  GPIOA->AFR[0]|= 0x000000010;//alternate function for port A 5
  TIM2->PSC = 840 - 1;     // Set prescaler
  TIM2->ARR = 1000;         // Set auto-reload
  TIM2->CCMR1 |= ( 0x6UL << TIM_CCMR1_OC1M_Pos );
  TIM2->CCMR1 |= TIM_CCMR1_OC1PE;
  TIM2->CR1 |= TIM_CR1_ARPE;
  TIM2->CCER &= ~TIM_CCER_CC1P;
  TIM2->CCER |= TIM_CCER_CC1E;
  TIM2->CR1 |= TIM_CR1_URS;
  TIM2->EGR |= TIM_EGR_UG;
  TIM2->DIER |= ( TIM_DIER_CC1IE | TIM_DIER_UIE );
  TIM2->SR &= ~( TIM_SR_CC1IF | TIM_SR_UIF );

这是代码，希望有人能帮忙

我尝试交换替代功能的位，但它不起作用，也许我只是不知道如何摆弄它

Answer 1

  RCC->APB1ENR |= RCC_APB1ENR_TIM2EN;
  RCC->AHB1ENR |= RCC_AHB1ENR_GPIOAEN;
  GPIOA->MODER |= ( 0x2UL << GPIO_MODER_MODE5_Pos); //alternate mode
  GPIOA->AFR[0]|= 0x000100000;//alternate function for port A 5
  TIM2->PSC = 840 - 1;     // Set prescaler
  TIM2->ARR = 1000;         // Set auto-reload
  TIM2->CCMR1 |= ( 0x6UL << TIM_CCMR1_OC1M_Pos );
  TIM2->CCMR1 |= TIM_CCMR1_OC1PE;
  TIM2->CR1 |= TIM_CR1_ARPE|TIM_CR1_CEN|TIM_CR1_URS;
  TIM2->CCER &= ~TIM_CCER_CC1P;
  TIM2->CCER |= TIM_CCER_CC1E;
  TIM2->EGR |= TIM_EGR_UG;
  TIM2->DIER |= ( TIM_DIER_CC1IE | TIM_DIER_UIE );
  TIM2->SR &= ~( TIM_SR_CC1IF | TIM_SR_UIF );

这是最终有效的代码，感谢 Ilya 和 pmacfarlane